1. Field of the Invention
The present invention relates to a biosensor, and in particular, to a surface plasmon resonance sensor including a semiconductor laser device for performing resonance amplification, to thereby proceed with optical amplification of a minor biological detection signal and for the convenience of signal detection.
2. Description of the Related Art
Due to specificity of a biosensor, a predetermined enzyme or reactants against predetermined analytes for reacting therewith are needed and are provided within a sample and the biosensor of various types can be thus designed according to electrical, optical, and mass differences before and after a bio-reaction. Due to the relative weak interaction between biomolecules, useful signals may possibly immerge by an interference signal due to the poor processing of weak signals. A common detection method used in a biosensor is to detect biological reaction signals by surface plasmon resonance (SPR) effects.
The surface plasmon resonance (SPR) detection method is basically achieved by total reflection of light on a surface of the metal film, thereby causing evanescent waves within the metal film. Additionally, a reflected light intensity is detected with a tremendous decrease while resonance occurs between the evanescent wave and the surface plasmon. For the SPR detector, the detection intensity is typically improved by changing surfaces of the metal films and structures of the detected surface. As described in U.S. Pat. No. 5,991,048, an inter-electrical media layer is used as a way to improve sensitivity of the metal film and the detecting surface. However, the SPR techniques use only detection of a single or multiple reflection of light and the detected signals are not effectively amplified.